JPH0716758B2 - Core joining method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for joining cores, which joins two or more cores formed separately.

[Prior Art] Conventionally, as a method of manufacturing a composite core in which two cores are integrated, it is disclosed in Japanese Patent Publication No. 50-38052, and as shown in FIG. The convex portion of the core 1 is fitted into the fitting concave portion 4 of the lower model die 3, and then the second
The first core 1 and the second core 2 are formed by blow molding sand for molding the core 2.
A method of integrating the core 2 with the core 2 is known.

However, the above-mentioned conventional method has a problem that it takes a long time to perform blow molding, which causes an increase in cost when joining a plurality of cores.

On the other hand, as another method of manufacturing a composite core in which two or more cores are integrated, a method of joining cores with an adhesive is known. However, this method using an adhesive has a problem that the process is complicated and the cost is increased when joining a plurality of cores.

[Object of the Invention] The present invention has been made in consideration of the above-mentioned problems of the related art, and a plurality of cores can be formed by simplifying the process and joining two or more cores in a short time. An object of the present invention is to provide a method for joining cores, which can reduce the cost at the time of joining.

[Structure of Invention]

In order to achieve the above object, a method for joining cores according to the present invention is a method for joining cores, in which at least two cores are separately formed and then these cores are joined together.
One core is used as a shell core, and a recess having an inner surface that can be fitted to the outer peripheral surface of the other core is formed in this shell core, then both cores are fired, and then the above-mentioned core While cooling the other core to room temperature while keeping the core at the firing temperature, the inner surface of the recess of the shell core and the outer peripheral surface of the other core are fitted together, and then the shell core is cooled to cool the shell. The inner surface of the recess is joined to the outer peripheral surface of the other core by the cooling shrinkage of the core, so that the shell core and the other core are easily joined.

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, the composite core 17 includes a second core 11 and a third core so as to surround the ring-shaped first core (the other core) 10.
It is joined with 13.

The composite core 17 is manufactured by the following steps. First, the first core 10, the second core 11, and the third core 13 are formed separately. At this time, the second core 11 and the third core 13 are made of fine silica sand mixed with resin to form a shell core, and a convex portion is formed on the outer periphery of the first core 10. 10a, 10a are formed, and the convex portion 10 is formed on the second core 11 and the third core 13.
Recessed portions (recesses) 11a and 13a that can be inserted into a and 10a are formed.

Next, the first core 10 is cooled to room temperature while keeping the second core 11 and the third core 13 at the firing temperature. Then the first core
The convex portions 10a, 10a of 10 are fitted with the concave portions 11a, 13a of the second core 11 and the third core 13, respectively. At this time, since a slight draft is formed on the side surfaces of the convex portions 10a, 10a of the first core 10, they can be fitted very easily.

After that, the second core 11 and the third core 13 are cooled, and the second core 11 and the third core 13 are thermally shrunk, so that the inner peripheral surfaces of the concave portions 11a and 13a are formed. The first core at the joint surface 15 and 15 and the joint surface 16 and 16 where the outer peripheral surfaces of the convex portions 10a and 10a are joined
10 and the second core 11 and the third core 13 are joined.

The composite core 17 thus produced is shown in FIG. 2 (a).
As shown by arrow I, the core setter jig 18 is used to fit in the recess 14a of the main mold 14, and then the main mold 19 is moved as shown by arrow II to cover the composite core 17. Then, the B surface is aligned with the A surface of the main mold 14. As a result, the composite core 17 is surrounded by the recess 14a of the main mold 14 and the recess 19a of the main mold 19.

Next, in FIG. 2 the core 11 and the third core 13 and the cavities 12.12 surrounded by the first core 10 and the second core 11 and the third core 13 and the main molds 14 and 14. A pair of disc brakes is produced by supplying the molten metal to the enclosed cavities 21 and 21 from the sprue 20 shown in FIG. 2 (b), and then cooling the molten metal.

[Second Embodiment] A second embodiment of the present invention will be described below with reference to FIG. The members having the same functions as those in the first embodiment are designated by the same reference numerals.

As shown in FIG. 3, the composite core 17 includes a second core 23 and a third core 23.
The ring-shaped first core (the other core) 22 by the core 24
The second core 23 and the third core 24 are joined to each other so as to sandwich them.

The composite core 17 is manufactured by the following steps. First, after cooling the first core 22 and the second core 23 having the hollow shaft-shaped portion 23a to room temperature, the outer peripheral surface of the hollow shaft-shaped portion 23a and the inner peripheral surface of the first core 22 are Fit together.

Next, while maintaining the firing temperature of the ring-shaped third core 24, the inner peripheral surface of the third core 24 and the hollow shaft-shaped portion 23a of the second core 23 are
It is fitted to the second core 23 so as to contact the outer peripheral surface of the.
At this time, the first core 22 is held between the second core 23 and the third core 24.

Next, the third core 24 is cooled and the third core 24 is thermally shrunk, so that the second core 23 and the third core 24 are joined together at the joint surface 25 between the second core 23 and the third core 24. The core 24 is joined to the core 24, and the first core 22 is also sandwiched between the second core 23 and the third core 24. As a result, the composite core 17 composed of the three cores 22, 23 and 24 is produced.

〔The invention's effect〕

As described above, the core joining method of the present invention uses one of the at least two cores as a shell core, and fits this shell core to the outer peripheral surface of the other core. After molding the recess having the inner surface to be obtained, both cores are fired, and then the other core is cooled to the room temperature state while maintaining the shell core at the firing temperature, and then the inner surface of the recess of the shell core and the other It is a method of cooling the shell core after fitting the outer peripheral surface of the core.

Therefore, the above method is due to the cooling shrinkage of the shell core,
Since the outer peripheral surface of the other core and the inner surface of the recess of the shell core are in close contact with each other, the shell core can be joined to the other core.

Therefore, in the above method, two or more cores can be joined by a very simple method of cooling the shell core, so that a significant cost reduction can be achieved when a plurality of cores are joined. Produce the effect of.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention, and FIG. 2 shows a manufacturing step when a disc brake is manufactured by using the core manufactured by the present invention. (a) is a sectional view, (b) is an explanatory view when supplying molten metal, FIG. 3 is a sectional view showing a second embodiment of the present invention, and FIG. 4 shows a conventional core joining method. FIG. 10.22 is the first core, 11.23 is the second core, 13.24 is the third core, and 15.16 is the joining surface. In the first embodiment, the first core 10 is used.
Is the other core, the second core 11 and the third core 13 are shell cores, and in the second embodiment, the first core 22 and the second core 23 are the other cores. , The third core 24 constitutes a shell core.

Claims (1)

[Claims] 1. A method for joining cores, wherein at least two cores are formed separately and then these cores are joined together.
One core is used as a shell core, a recess having an inner surface capable of fitting to the outer peripheral surface of the other core is formed in the shell core, both cores are fired, and then the core While maintaining the firing temperature of the core, after cooling the other core to a room temperature state, the inner surface of the recess of the shell core and the outer peripheral surface of the other core are fitted, and then the shell core is cooled. How to join cores.